摘要
以川北地区朝天关口村大隆组典型野外剖面及邻区其他剖面为例,通过野外剖面观察、岩石薄片和微体古生物化石薄片观察鉴定等方法,分析其垂向及平面的岩相及沉积相展布及变化,结合区内已有钻井、地球化学主微量元素、总有机碳(TOC)、物性及微孔隙等参数来探讨其页岩的勘探潜力。研究结果表明:(1)大隆组地层纵向上自上而下发育一套灰色硅质灰岩、灰黑色灰质页岩、灰黑色碳质页岩、泥岩组合,其中大隆组二段硅质灰岩和泥质灰岩中含有大量的菊石、牙形石、放射虫化石,大隆组一段碳质页岩和钙质页岩中则含有少量有孔虫、介形虫、双壳类、腹足类以及腕足等化石;(2)大隆组页岩沉积环境属于缺氧—贫氧咸水环境,利于有机质的保存与富集;(3)大隆组页岩有机质类型为Ⅱ1型、有机质丰度高,处于成熟—高成熟演化阶段,孔隙主要发育粒间孔、粒内孔与有机质孔,大隆组二段黑色页岩孔隙度较高,脆性矿物质量占比高,页岩可压裂性好,具有良好的页岩气富集成藏地质条件。综上分析认为,川北地区大隆组页岩整体具有较好的页岩气资源潜力,可作为下一步页岩气勘探的后备层位。
In this study,we analyze the distribution of vertical and horizontal lithofacies as well as the sedimentary facies of a typical field section of the Dalong Formation in Guankou Village of Chaotian District in northern Sichuan,based on field observations and the identification of thin sections of rock and micropaleontological fossils.We then discuss the potential for shale exploration based on data from wells in the area,the main and trace geochemical elements in it,its total organic carbon content,physical properties,and micropores.The results showed the following:(1)A set of assemblages of gray siliceous limestone,gray-black calcareous shale,gray-black carbonaceous shale,and mudstone had developed from top to bottom in the Dalong Formation.The siliceous limestone and argillaceous limestone in the upper Dalong Formation contained a large amount of ammonites,conodonts,and radiolaria fossils,while the carbonaceous shale and calcareous shale in the lower Dalong Formation contained a small amount of Rhizaria,ostracods,bivalves,gastropods,and brachiopods.(2)The sedimentary environment of shale in the Dalong Formation had an anoxic-poor oxygen-saline water environment that was conducive to the preservation and enrichment of organic matter.(3)The organic matter of shale in the Dalong Formation was of theⅡ1 type.It was highly abundant,and was in the mature stage of its evolution.The pores mainly consisted of intergranular pores,intraparticle pores,and organic matter pores.The black shale in the upper Dalong Formation was highly porous and contained a large amount of brittle minerals.The shale had good fracture-related properties and suitable geological conditions for the accumulation of shale gas.In sum,shale in the Dalong Formation in northern Sichuan has considerable potential for extraction,and it can be used as a backup reservoir for the exploration of shale gas.
作者
陈更生
王林琪
石学文
杨雨然
朱逸青
蒲飞龙
杨雪
王青
徐浩
CHEN Gengsheng;WANG Linqi;SHI Xuewen;YANG Yuran;ZHU Yiqing;PU Feilong;YANG Xue;WANG Qing;XU Hao(Shale Gas Research Institute of PetroChina Southwest Oil&Gas Field Company,Chengdu 610051,China;College of Energy(College of Modern Shale Gas Industry),Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China)
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2024年第3期361-378,共18页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
中国石油天然气股份有限公司西南油气田分公司页岩气研究院科技专项项目(XNS页岩院JS2022-26)
“成都理工大学2022年中青年骨干教师发展资助计划”资助项目(10912-SJGG2022-07702)。
关键词
四川盆地
大隆组
野外剖面
页岩储层特征
勘探潜力
Sichuan basin
Dalong Formation
field section
shale reservoir characteristics
exploration potential
